How Much Does Ospf Cost

The Cost formula is reference bandwidth divided by interface bandwidth. The default reference bandwidth of 100 Mbps is used for OSPF cost calculation. For example, if we have an Ethernet interface (10 Mbps), the OSPF path cost value is 100 Mbps / 10 Mbps = 10.

How does Cisco router calculate OSPF cost?

1. Interface Cost= Reference bandwidth/interface bandwidth.
2. Hence By default Interface Cost= 10^8/(interface bandwidth)
3. The “auto-cost reference-bandwidth” command allows you to change the reference bandwidth that OSPF uses to calculate its metrics:
4. Router#configure terminal.

What is OSPF cost preferred?

Routes with the better metric are preferred. Open Shortest Path First (OSPF) uses cost as the metric calculated, based on the bandwidth of the link. The cost of a link is calculated by dividing the reference bandwidth (100 Mbps by default) by the interface bandwidth.